The selection of rolling bearing fit can be divided into the following situations:

Bearing condition: when the load is large, the fit with larger interference should be adopted; under the rotating load, the tight fit should be selected; when the local load is applied, the loose fit should be selected generally;

Working temperature: Generally speaking, the temperature of bearing ring is higher than that of adjacent parts. When the inner ring temperature is higher than the shaft temperature, the tight fit should be selected; when the outer ring temperature is higher than the bearing hole temperature, the loose fit should be selected.

Speed and rotation accuracy: for bearings with high speed and strong vibration, a tight fit should be selected. Too loose fit is unfavorable to improve the rotation accuracy of bearings and reduce vibration.

Assembly and disassembly: the bearing which is often installed, disassembled or replaced, especially the bearing on heavy machinery, should choose a loose fit.

For the bearing at the free end, the outer ring and the seat hole shall have a loose fit.

Measures to improve the shaft stiffness are as follows:

(with the increase of stiffness, the rotation accuracy will be increased, and the noise and vibration will be reduced)

Improve the stiffness of bearing pedestal

The stiffness of the support can be increased by increasing the wall thickness and reinforcing ribs

Reasonable arrangement of bearing combination

The same fulcrum:

Poor rigidity of front mounting         Good rigidity in reverse installation

Different fulcrum:

Simple support:

       Poor rigidity of front mounting               Good rigidity in reverse installation

Cantilever:

     Poor rigidity of front mounting             Good rigidity in reverse installation

Bearing preloading

Objective: to eliminate the clearance of bearing, improve the stiffness and rotation accuracy of shafting, reduce vibration and prolong service life.

Preloading: in installation, an axial force is generated and maintained in the bearing to eliminate the axial clearance in the bearing and produce initial deformation at the contact between the rolling element and the inner and outer rings.

method:

Clamp the outer rings of a pair of tapered roller bearings

Pre tightening with spring

Insert sleeves of unequal thickness between bearings

Add metal gasket and preload between rings

Narrow the ring and apply preload